On a collection of hydroids (Cnidaria, Hydrozoa, Hydroidolina) from the west coast of Sweden, with a checklist of species from the region 3171 Author Calder, Dale R. text Zootaxa 2012 2012-01-24 3171 1 1 77 https://biotaxa.org/Zootaxa/article/view/zootaxa.3171.1.1 journal article 10.11646/zootaxa.3171.1.1 1175­5334 5247704 Rhizorhagium roseum M. Sars , in G.O. Sars, 1874 Fig. 12 Rhizorhagium roseum M. Sars , in G.O. Sars, 1874: 129 .— Rees & Rowe, 1969: 10 . Perigonimus roseus .— Lönnberg, 1902: 173 .— Jäderholm, 1909: 46 , pl. 3, fig. 7.— Jägerskiöld, 1971: 64 . Type locality. Norway : Mangerfjord , Bognestrømmen , 20 fm ( 37 m ) ( Rees 1956b: 114 ) . Museum material. Kosterhavet, 58°53.093’N , 11°05.668’E , 20–30 m , 09.ix.2010 , biological dredge, R / V Nereus , two colonies, up to 5 mm high, on stems of Tubularia indivisa and Lafoea gracillima , without gonophores, ROMIZ B3909. Remarks. Gonophores were lacking in studied material, but the trophosome of Rhizorhagium roseum M. Sars , in G.O. Sars, 1874 , with its stolonal habit, long hydrocaulus, thin pseudohydrotheca, single tentacular whorl, and nipple-shaped hypostome, as well as its reddish to pinkish hydranths that bend over when disturbed, is distinctive among hydroids in the biogeographic region. A detailed account of this small species, from boreal and subarctic waters on both sides of the Atlantic Ocean, has recently been given by Schuchert (2007) . Rees (1956b) examined type material of Rhizorhagium roseum and concluded from the original label that it was from “Bongnestrømmen” (Bognestrømmen) in the Mangerfjord, Norway . In addition to its occurrence on the west coast of Sweden (e.g., Jäderholm 1909 , as Perigonimus roseus ), R. roseum has been reported from the Oslofjord, Norway ( Christiansen 1972 ). Reported distribution. West coast of Sweden .—Kosterfjord to Gullmarfjord ( Rees & Rowe 1969 ). Elsewhere.—North Atlantic from the Barents and White seas to western Scotland in Europe ( Schuchert 2007 ), and from northern Foxe Basin in the Canadian Arctic to Buzzard’s Bay, Massachusetts , in eastern North America ( Calder 2004 ); eastern North Pacific from Alaska to southern Vancouver Island ( Fraser 1944 , as Garveia groenlandica ; Brinckmann-Voss 1996 ).